Refrigerating method and apparatus



Oct. 25, 1938. BUCHANAN 2,133,952

REFRIGERATING METHOD AND APPARATUS Filed March 3,. 1936 w EvnPoRnToR suawss avaponm-oa'sma wnLLs WITNESSES:

. ATTO EY v Patented Oct. 25, 1938 UNITED STATES PA ENT oFr-lce REERIGERAZHNGMETHQD Leslie B. IM. Buchanan,

or ,to Westinghouse Springfield, assign- Electric & Manufacturing flompany, East viitts burgh, Pa., corporation of Pennsylvania Application lMarclr 3, 1936, Serial .No. 66,808

Fr 1s My invention relates to :a method and apparatus for controlling the operation of refrigerating machines having relatively high and low tem-- perature cooling-elements and it has for an oh- 5 ject to provide an improved method and apparatus of this kind.

.A further object of my invention is to normally operate an evaporator element of .a refrigerator at a predetermined mean temperature and to effeet, at will, the operation of a second evaporator element at a lower temperature.

These and other objects are effected .by my invention as will be apparent from the following second evaporator elements is employed for cooling food products stored in the refrigerator and for congealing'dessertsor freezing water or other fluids.

Evaporation of refrigerant in one or the other of the evaporators is controlled by a control device adjustable to first or second positions. In the first position of the control device, refrigerant is evaporated in one evaporator for cooling;=

the air in the refrigerator chamber under control of a thermostat rranged in the chamber. This A eva'porator is, therefore, maintained at a predetermined mean temperature for cooling the air inthe chamber.

The control device may be moved to a second 40 position, whereupon evaporation is effected in the other evaporator, at relatively low pressure and temperature. This evaporator is effective for quick freezing purposes 'or for congealing des+ serts. In this position of the device, the thermostat is inefl'ective to control the evaporation of refrigerant in the evaporator. Means may be provided for. returningthe control device to its first position, which means is operated, preferably, in response to the temperature of the low temperature evaporator. A suitable adjustment may be provided for the control device whereby the temperature of the low temperature evaporator at which the device is actuated may be varied. The adjustment preferably includes a position 56 wherein the temperature responsive means is inconduits 22 and 23 are arranged eflfective to return the control device to its first position, so that evaporation of refrigerant con-,

tlnues in the low temperature evaporator until the device is manually moved to its .iirst position.

My improved control apparatus is applicable 5 .to various 'forms of (two temperature refrigerators :such as, :for example, the refrigerating apparatus disclosed and claimed in my copending application, No. 15,003, filed April 6, 1935, and assigned to the Westinghouse Electric 8: Manu- 1o facturing Company. .In "the present application, I have disclosed a similar refrigerating system which employs a :novel evaporator structure having wall members in heat exchanging relation with the air in :refrigerat'orchamber and shelves '15 for supporting water freezing trays arranged within the walls. Ihe wall members constitute a relatively high temperature evaporator element and the shelves define a. low temperature evaporator element. A system having an evaporator 20 H structure of'this type is disclosed and claimed, in my copending application, Serial No. 81,088, filed May 21, 1936, and assigned to the Westinghouse Electric 8: Manufacturing Company.

Referring specifically to the drawing for a de- 25 tailed description of the invention, a @refrigerator cabinet of the domestic type is shown generally at l0 and includes insulated wall members II for defining a chamber l2 for the storage and cooling of food products. An evaporator struc- 30' ture i3 is arranged within the chamber l2 and includes wall members I and I5 and shelves l6, l1, and I8, the latter supporting trays IS in which water or other fluids may be frozenor congealed. It will be understood that the of'the evaporator I2 are hollow or include passages in which refrigerantis evaporated for coolingthesame.

Liquid refrigerant enters the lower shelf It. by means of a conduit 2| and passes in series 40 through the shelves l6, l1, and I 8.. Connecting V respectively between the shelves ,l6 and "and between shelves l1 and i8 for conductingrefrigerant thereto. .;A

conduit 24- connects the shelf la and side wall 45 ll, thelatter being connected to the wall It by a conduit 25, as shown. vaporized refrigerant is conveyed fromthe-wall member I! through a conduit 26, so that it will be apparentthat the flow of refrigerant through the evaporator I3 is in series through shelves l6, l1, and I8 and the walls II and I! in the order named. This is il I lustrated diagrammatically in Fig. 2.

A refrigerant condensing unit, shown generally at 21, and preferably of the compression type,

walls and shelves 35 I shown diagrammatically at 32 and 33, respectively.

Aconventional float valve 34 for regulating the flow of condensed refrigerant to the evaporator is connected in the conduit 2|, and a device 35 that operates to vary, in effect, the refrigerant charge, is disposed between the valve 34 and the condenser 29. The latter device includes a casing having a chamber 36 thereinand a movable element 31 for varying the liquid storage capacity of the chamber 36, 'said element 31 being raised or lowered by a solenoid including a core 38 and a winding 39. The chamber 36 receives refrigerant from the condenser 29 through a conduit 4|.

When the element 31 is position,

in its first, or lower it occupies the chamber 36 and pre- -ve'nts the collection of condensedrefrigerant therein, and, therefore, substantially all of the refrigerant in the system is circulated by the compressor mechanism 28. Raising the element 31 to a second position. reduces the effectivecharge of refrigerant in the system, as condensed refrigerant gathers in the chamber 36 and does not circulate through the evaporator. The effective charge of refrigerant is, therefore, reduced in an amount equivalent to the amount of liquid which was displaced by element 31 when in'the.

first or lower position.

The purpose of varying the. effective charge of refrigerant is to change the operation of the system, so that in the first position of the device 35, cooling of the air in the chamber |2 to a desirable temperature is effected and'in the second position of the device, quick freezing of liquids at a low temperature is obtained without materially reducing the temperature of the air in the chamber |2. In the first position of the device, refrigerant fills the shelves and a substantial portion of the evaporator walls I4 and I5. This represents the normal operating position and, as described hereinafter, the compressor mechanism 28 is controlled by a thermostat 42 for maintaining the air within the chamber l2 at a desired temperature.

The temperature at which the evaporator op erates is preferably as high as practicable, and suillcientlyflow for effectively cooling the air in the. refrigefator chamber I2 and for maintaining the liquid in the trays l9 in a frozen condition, if desired. By maintaining the temperature of the evaporatorat a relatively high value, excessive dehumidification of the air in the chamber I2 is avoided.

In the second or quick freezing position of the 'device 35,. liquid refrigerant is present in the shelves", l1, and I8 only, due to the reduced amount of refrigerant in the;system that iseffective for evaporation. The walls l4 and I5 contain refrigerant which has been vaporized in the shelves, which refrigerant is superheated by the walls. The walls are, of course, cooled in a very small amount, the heat abstracted therefrom being only the sensible heat absorbed by the vapo'rized refrigerant as superheat. v

' In accordance wit my invention, operation of the compressor mechanism 28 is initiated or continued as the device 35 is actuated to its second positionand is terminated only when the temperature of the shelves is depressed to the desired value, at which time the device is returned to its first position. It is to be understoodthat the shelves I6, I1, and 18 are so disposed that they are shielded by the walls l4 and I5 sot that they arecontacted by only a small amount of the air circulating in the chamber I2, and therefore, are not eifective to cool the air to any substantial degree. Shields 43 may be carried by the evaporator l3 at its bottom, rear and front sides, for inhibiting air in the chamber I2 from circulating over the cold shelves.

In accordance with my invention, the device 35 and the condensing unit 21 are preferably controlled by a mechanism generally shown at 45. The latter includes a lever 46 pivoted at 41 and biased in counterclockwise direction by a tension spring 48 and in clockwise direction by a bellows 49. The bellows 49 communicates with a closed tube 5| which is secured in heat exchanging relation with one of the shelves |6 of of the evaporator l3. The tube 5| contains a volatile fiuid and defines with the bellows 49 a thermostat of the expansible gas type. Movement of the lever 46 by the bellows 49 is limited by a stop 52, which may be adjustable as shown.

A pair of electrically connected contacts 53 and 54 are carried by the lever 46 and are connected to a conductor L1 of an electrical circuit.

The-mechanism 45 includes a pair of contacts 55 and'56 insulated from each other and carried by flexible members 51 and 58, respectively. The members 51 and 58 are carried by a spring sup.- port 59 fixed to a stationary member at 6| and carrying, at its upper end a manually operated push button 62. The latter is threaded in the support 59 and includes an armature 63, forming a part of a magnet, shown at 64. The latter may be energized by a suitable winding which is electrically connected to the solenoid 39 in suchmanner that they are simultaneously energized and deenergized. As-shown, the solenoid 39 and winding 65 are series connected between a conductor L: of the electrical supply circuit and thecontact 55.

The running and starting windings 32 and 33 of the compressor motor are connected to the conductor Ia and to a conventional starting re- 19.37 66. The latter includes a switch 61 for controlling energization of starting winding 33 and a solenoid 68 for actuating the switch 61 and connected to the runni g winding 32 in series relation. During starti g, the relatively high starting current in the solenoid 68 effects closiii) The motor winding 32 is connected to the con ductor L1 by parallel-circuits, the firstof which Operation The refrigerating system disclosed operates on the well-known compressorcondenser-expander cycle. Gaseous refrigerant is withdrawn from the evaporator structure l3 throiighconduit 28 by the compression mechanism 28 and is com-' upon the position of the pressed to a suitable pressure for condensation in the condenser 29. Heat is abstracted from the condenser in any well known manner for condensing the compressed refrigerant. Liquid- 'refrigerant passes through the conduit 4| and device '35 to the float valve 34, which regulates the delivery of the refrigerant to the evaporator I 3 through the conduit 2|. vaporization of the refrigerant in the'evaporator H3 at relatively low pressure is effected, whereby heat is abstracted therefrom. The portion or portionsof the evaporator in which vaporization is efiected depends device 35 as described heretofore.

During normal operation for cooling the air in the chamber IS, the apparatus is in the position shown in the drawing. The device 35 is deenergized and the element 31 occupies the chamber 36 so that liquid refrigerant occupies the shelves [6, l1, and I8 and a substantial portion of the walls I4 and H5. The compressor mechanism 28 is under control of the thermostat 42. As the temperature within the chamber [2 increases, the thermostat 42 closes and completes a circuit including conductor L1, thermostat 42, relay solenoid 68, motor winding 32 to the conductor In so that the compresor 28 operates to circulate refrigerant in the system. Evaporation is effected in the shelves l6, l1, and I8 and walls I 4 and i whereby thechamber I2 is cooled and the congealed substance in the, trays l9 may be preserved. As the temperature within the chamber. 12 is depressed to a predetermined value, the thermostat 42 opens and operation of the compressor 26 is terminated.

When it is desired to depress the temperature of the shelves, as When water is to be frozen or dessert congealed, the button 62 of the mechathe contacts 54 and 56 deenergizes-the shunt cir-.

nism 45 is pressed. This operation eifects closing of contacts 53 and 55 and establishes a circuit including conductor L1, lever 46, contact 53 and 55, winding 65, solenoid 39 to conductor L2.

Energization of magnet 64 attracts the armature 63 to the core and holds the button 62 and the member 55 in this position. Engagement of the contacts 54 and 56 establishes a shunt circuit around the thermostat 42 and eifects'operation of the compressor mechanism 28, regardless of whether thermostat '42 is closed or not. .As the solenoid 39 is energized, the element 31 is raised and liquid refrigerant fills the chamber 36 so that the effective charge of refrigerant is reduced. Therefore, refrigerant substantially fills the shelves E6 to l8, inclusive, and is vaporized therein, the vaporous refrigerant passing through the walls i4 and I5 to the suction conduit 26;

The temperature of the shelves 16 to I8 is depressed to a relatively low value foreffecting the congelation of the substance in the trays without materially reducing the temperature in the chamber I2. shelves is depressed to a predetermined value, the bellows 49 contracts and the lever 46 ismoved by the spring 48 a distance sufficientto effect opening of the contacts 53 and 55. Accordingly, the magnet 64 is deenergized and the spring meinber 59 moves to the right. Opening of contacts 53 and55 deenergizes solenoid 39, permitting the element 31 to drop to its lower position and thereby displace the refrigerant in chamber 36, which refrigerant passes to the float 34 and eventually to the evaporator walls l4 and I5. Opening of cuit around the thermostat 42 so that control As the temperature of the' of energization of the motor winding 32 is returned to the thermostat 42.

The temperature of the shelves at which the bellows 49 operate to open the contacts 537 and 55 may be varied by rotating the button 62, which shelves to effect opening of the contacts 53 and 55. V I

Preferably, the button 62 includes a position wherein the bellows 49 is ineffective to open the contacts 5355. Opening of the contacts may, however, be effected manually by pulling the button and armature 63 from the magnet 64. This operation may be obtained by providing a stop H which is engaged by an extension 12 on the lever 46. By adjusting the armature to its extreme position wherein the armature 63' is farthest removed from the magnet 64, maximum deflectionof the contact supports 51 and 58 is effected when the button 62 is pressed. In this position, the spring 48 is ineffective to, move the lever 46 and contact 53 a distance sufilcient to disengage the contact 53 from contact 55 due to the engage- -ment of the stop IL and the lever extension 12.- Continuous operation of the compressor 28 isefiected' in this position and operation thereof is terminated only by manually pulling the arma-' ture 63 away from the magnet core and thereby disengaging contacts 55 and 56 from the contacts 53 and 54.

'I have shown my improved control apparatus applied to a refrigerating system employing high and low temperature evaporating elements wherein the effective charge of the refrigerant in the system is varied for controlling evaporation in one of the elements, but it is to be understood that it may be applied to other forms of refrigerating systems having a plurality of evaporating elements which are operated at different tempera'- I "control system wherein the compressor mechanism is controlled at timesby a thermostat which is responsive to the temperature of the air.in

the chamber cooled by one of the evaporator elements, but it will be understood that the thermostat may be disposed otherwise and may the made responsive to other temperatures prevailing in the chamber in any known manner.

From the foregoing, it will be apparent that I have provided an improved control system for refrigerating apparatus, having a refrigerant condensing unit and a plurality of evaporators, in which the condensing unit'is operated to supply refrigerant for vaporization, in one 'of the evaporators under controlof a thermostat at onetime, and in which the condensing unit may be started independently of the thermostat at another time to supply refrigerant for vaporization in a second evaporator, the operation of said.

but one art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, thatonly such limitations shall be placed thereupon as'are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is: I

1. In refrigerating apparatus, the combination of a cabinet structure, a low temperature sponsive to the temperature of the low temperand a higher temperature evaporator disposed within said cabinet structure, refrigerant condensing means, means for conveying condensed refrigerant to said evaporators, temperature responsive means arranged within the cabinet for controlling the operation of the refrigerant condensing means, a device normally disposed in a first position in which refrigerant is delivered for vaporization in the higher temperature evaporator and in which position the temperature responsive means is effective for controlling the refrigerant condensing means; said device being movable manually to a second position in which refrigerant is delivered for vaporization in the low temperature evaporator and in ,which position therefrigerant condensing means is operated independently of the temperature responsive means, and means responsive to a predetermined temperature of the low temperature evaporator for actuating said device to 'its first position.

. 2. In refrigerating apparatus, the combination of a cabinet structure, a low temperature and a higher temperature evaporator disposed within said cabinet structure, refrigerant condensing means, means for conveying condensed refrigerant to said evaporators, a device movable to first and second positions in which positions refrigerant is delivered for vaporization in the high and low temperature evaporators, respectively, temperature responsive means arranged within the cabinet for initiating and terminating oper-. ation of the refrigerant condensing'means when said device is in its first position, meansfor controlling said device and having first and second positions, corresponding to the first and second positions of said device, means for manually actuating the control means to its second position and for initiating operation or the refrigerant condensing means independently of said temperature responsive means, and means reature evaporator for actuating the control means to its firstposition and for returning control of the refrigerant condensing means to said firstmentioned temperature responsive means 3. In refrigerating apparatus, the combination of a cabinet structure, a low temperature and a higher temperature evaporator disposed within said cabinet estructure, refrigerant condensing means, means for conveying condensed refrigerant to said evaporators, temperature responsive means arranged within the cabinet for controlling the operation of the refrigerant condensing means, a device normally disposed in a first position in which refrigerant is delivered for vaporization in the higher temperature evaporator and in which position the temperature responsive; means is effective for controlling the refrigerant condensing means; said device .being movable manually to a second position in which refrigerant is delivered for vaporization in the low temperature evaporator and in which position the refrigerant condensing means is operated independently of the temperature responsive means;

form, it will be obvious tothose skilled in the means responsive to a predetermined temperature of the low temperature'ev'aporator for actu- -ating said device to its first position, and means movable to a plurality of selective positions for adjusting said last-mentioned temperature responsive means, whereby the temperature of the low temperature evaporator to which the temperature responsive means responds to adjust said device is varied.

4. The combination as claimed in claim 3 wherein said adjustable means includes a position in which the last-mentioned temperature responsive means is rendered ineffective to actuate the control device to its first position.

5. In refrigerating apparatus, the combination of a cabinet, a relatively high temperature evaporator for cooling the air within the cabinet, 9. relatively'low temperature evaporator for congealing fluids, means for condensing refrigerant and for translating it to said evaporators, a device movable to a first position for delivering condensed refrigerant. to the high and low temperature evaporators and movable to a second position for delivering condensed refrigerant to the low temperature evaporator only, temperature responsive means disposed within the cabinet for controlling the operation of the refrigerant condensing. means whenv said device is in its first position. means for moving said device condensed refrigerant and movable to first and second positions; said device when disposed in its first position, delivering condensed refrigerant to the high and low temperature evaporators and,

when disposed in-its second position, delivering condensed refrigerant to the low temperature evaporator only; means responsive to temperatures prevailing within the cabinet for initiating and terminating operation of the refrigerant condensing means when said device is in its first position, means for manually adjusting the device to its second position and for operating the refrigerant condensing means independently of the temperature responsive means and means responsive to a predetermined temperature of the low temperature evaporator for moving said device to its first positionand for returning control of the refrigerant condensing means to said first-mentioned temperature responsive means.

'7. In refrigerating apparatus, the combination of a cabinet structure, a low temperature and a higher temperature evaporator arranged within said cabinet structure, means for condensing vaporous refrigerant and for translating it to said evaporators, adevice for controlling the flow of condensed refrigerant and movable to first and second positions; said device, when disposed in its first-position, delivering condensed refrigerant to the high and low temperature evaporators and, when disposed in its second position, delivering condensed refrigerant to the lowtemperature evaporator only; means responsive to temperatures prevailing within the cabinet for initiating and'terminating operation of the revice to its second position for operating the refrigerant condensing means independently of the, temperature responsive means and .for moving said device to its first position for returning control of the refrigerant condensing means to said first-mentioned temperature responsive means.

8. In refrigerating apparatus, the combination of a cabinet structure, an evaporator arranged within said cabinet structure, said evaporator having wall members for cooling the air in. said cabinet and constituting a high temperature evaporator element, said evaporator including shelves arranged within the wall members for receiving fluids to be congealed and constituting a low temperature evaporator element, means for condensing refrigerant and for translating it serially through said shelves and said wall members, temperature responsive means disposed within the cabinet for controlling the operation of the refrigerant condensing means, a device for varyingthe eifective charge of refrigerant in the apparatus and movable to a first position in which condenser refrigerant fills said shelves and a portion of the wall ,members, said'device being movable to a second position in whichcondensed refrigerant is delivered to theshelves only, means manually operated'at will for actuating said device to its second position and for operating the refrigerant condensing means independently of the temperature responsive means, means re sponsive to a predetermined temperature of a shelf for actuating the device to its first position and for returning control of the refrigerant condensing meansto the first-mentioned temperature responsive means and means adjustable to a plurality of selective positions for varying the temperature of the shelves to which said temperature responsive means responds -to actuate said device; said adjustable means including a posi-' of a low temperature evaporator, ahigher tem-l' perature evaporator, refrigerant condensingx means, means for conveying condensed refrigerant to said evaporators, temperature responsive means affected by said higher temperature evaporator for controlling the operation of the refrig; erant condensing means, a device. normally dis? posed in a first position in which refrigerant is delivered for vaporization in the higher temperature evaporator and in which position the temperature responsive means is efiective for con-.

trolling the refrigerant condensing means; said device being niovable manually to a second position' in which the refrigerant is delivered for vaporization in the low temperature evaporator and in which position the refrigerant condensing means is operated independently of the temperature responsive means, and means responsive to a predetermined temperature of the low temperature evaporator for actuating said device toits I the air in-the zone and a. second portion isolated first position. t 10. In refrigerating apparatus, the combination of a structure having a zone 'to'be refrigerated, an evaporator having a first portion forcooling' from said zone, means for circulating refrigerant through the evaporator, temperature responsive means for controlling the operation. of the circu- K evaporator has been satisfied.

lating meanswhereby the air in said zone is maintained at a predetermined mean value,- auxiliary means for effecting operation of the circulating means independently of the temperature responsive means whereby the temperature of the second evaporator portion. is depressed to a relatively low value and means-for reestablishing control of the circulating means by the temperature responsive means subsequent to an operation of the circulating means which was effected by said.

auxiliary means.

.11. In refrigerating. apparatumthe combination of a structure having a zone to be refrigerated,

an evaporator having a first portion for cooling the air in the zone, a container for fluid to be congealed, said evaporator having a second. portion inheat transfer relation with the container, means for circulating, refrigerant through the evaporator, temperature responsive means for controlling the operation of the circulating means whereby the air in said zone is maintained at a predetermined meafivalue, means'manually' operable at will for effecting operation of the circulating means independentlyof the temperature responsive means whereby the temperature of 'the second evaporator portion is depressedto a rela-.

tively low value for rapid congealation of the fluid in the container and means responsive to the tem- I 12. In refrigerating apparatus, the combination of a cabinet structure, a low temperature and a higher temperature evaporator disposed within said. cabinet structure, refrigerant condensing means, means for conveying condensed refrigerant to said evap'orators, temperature responsive means arranged within the cabinet for controlling the operation of the refrigerant condensing means, means normally effecting refrigeration in the higher temperature evaporator, at which time the temperature responsive means controls the refrigerant condensing means, said last means be-- ing manually adjustable to efl'ect refrigeration of the low temperature evaporaton atwhich time the refrigerant condensing means is operated independently of' saidtemperature responsive means, and means re'sponsiveto a predetermined temperature of the low temperature evaporator for again effecting refrigeration of the higher temperature evaporator under the control of the temperature responsive means. a

13. In refrigerating apparatus, the combination of a cabinet structure'a low temperature'and a higher temperature evaporatordisposed within said cabinet structure, "refrigerant condensing means, means for conveying condensed refrigerant to said evaporators, temperature responsive meansarranged within the cabinet for controlling the operation of the refrigerant condensing l means, a mechanism for normally effecting're- I for adjusting the mechanism for effecting refrig- "eration of the low temperature evaporator, at

which time the temperature responsive means is ineifectivexto control the refrigerant condensing means,and means for conditioning said mechanism so that refrigeration is again effected inthe higher temperature evaporator, whenthe de-' mand for refrigeration of the low temperature 14. In refrigeratingapparatus, the combination of means defining a zone to be cooled, an evaporator structure including wall members disposed in heat transfer relation with the air in said zone 5 and defining a cooling chamber-therebetween,

said structure including a shelf disposed within said cooling chamber and isolated from the air in the zone, said wall members and shelf having respective spaces therein for refrigerant, means for circulating refrigerant through the evaporator structure and adjustable to a first condition for supplying condensed refrigerant to the spaces of the walls and shelf for vaporization and to a second condition for supplying refrigerant to the shelf space only, means responsive to the temperature of the air in said zone for controlling the operation of the circulating means during periods when the latter is in said first condition, means for effecting operation of the circulating means independently of .the temperature responsive means when the circulating means is in said second condition, and means responsive to apredetermined low temperature of the shelf for adjusting the circulating means. to its first condition and for returning control of v having respective passages for refrigerant, means for condensing refrigerant and for translating it to the evaporator so that it flows into the shelf passage until filled and thence into the passages of the walls, a device for varying the effective charge of refrigerant in the apparatus and norcontrolling the operation of the refrigerant condensing means during periods when said device is normally disposed in its first position, means for periodically actuating said device to its second position and for operating the refrigerating con- 'shelf and the wall members for vaporization at relatively high pressure, controlling the supply of refrigerant in response to the temperature within said space, supplying refrigerant to the shelf for vaporization at relatively low pressure independently of the temperature of said space and establishing the said normal supply of refrigerant to both the shelf and the walls under control of the temperature within the space in response to a predetermined low temperature produced by CERTIFICATE OF CORRECTION. Patent No 2,1 ,952. October 25, 1958.

LESLIE B. M. BUCHANAN.

It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correction as fella/vs: Page 5, first column, line 25, claim8, for the word "condenser" read condensedjandthat the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of December, A. D. 1958.

Henry- Van Arsdale (Seal) Acting Commie sione r of Patent :3 

